The main objective of the proposed research is to test hypotheses concerning the conditions under which stress inoculation and related interventions by an adviser will augment a person's commitment and adherence to a difficult course of action that entails suffering short-term losses in order to attain long-term gains. The research will consist of field experiments with subjects making real decisions affecting their health. We plan to investigate hypotheses that take account of the following concepts that may help to explain how stress inoculation influences the way people cope with postdecisional stress: vigilant coping patterns, self-esteem enhancement, self attributions and perceived control. Controlled field experiments will be conducted in the setting of our Yale Weight-Reduction Clinic, where we can assign subjects on a random basis to treatment conditions and obtain weight loss measures as indicators of adherence to the recommended diet, supplemented by attitude measures to assess mediating processes that might account for the observed effects of the interventions. We shall also include personality scales and other predispositional measures in order to determine which types of person respond favorably to the interventions and which do not. We also plan to use other field settings that lend themselves to systematic research on adherence to health rules--for example, medical clinics. The studies are intended to enable us to identify and explain the conditions under which stress in oculation and related interventions induce decision makers to commit themselves to follow health rules with fuller awareness of negative consequences and subsequently to adhere to the decision, with a minimum of backsliding.